Many personal care compositions on the market today contain essential oils as fragrances, and more recently as active ingredients useful for the treatment of a variety of ailments. Such uses have been generated out of the interest associated with aromatherapy, in which various essential oils are vaporized and inhaled by the user. This practice has led to the use of rosemary and lavender oils for relaxation, eucalyptus and citrus oils for the treatment of respiratory infections, and a variety of other novel oils used as analgesics, muscle relaxants and the like.
Essential oils are a mixture of chemical entities, the majority of which are terpene-like materials. Each essential oil comprises a unique mixture of terpenes and other similar materials that provide the individual fragrance and activity of the essential oil. The composition of an essential oil is dependent not only upon the source of the oil, but also upon the method of extraction. Different extraction methods can generate essential oils having differing levels and ratios of important components, and this in turn can result in essential oils having different fragrance and activity profiles, despite being isolated from the same source.
A problem associated with essential oils is the fact that they can contain auxiliary fragrance materials some of which are recognized as potential allergens and/or irritating agents. These materials, in a proportion of the population, can cause hypersensitivity-type reactions, or skin irritation, manifested as skin redness, burning, itching, and in severe cases, edema and skin peeling. Unfortunately, these same auxiliary fragrance materials such as limonene, linalool, benzyl alcohol and geraniol in combination with terpenes such as α- and β-pinene and α-phellandrene are typically fundamental to the fragrance of the essential oil and, in some instances, required for the purported aromatherapeutic activity of the oil in question. By simply eliminating these auxiliary fragrance materials in the essential oil, the oil typically does not meet the user's expectation in both fragrance impact and roundness and aromatherapeutic activity. Therefore, a need exists for personal care compositions comprising essential oils or materials thereof, which have improved allergen profiles. More precisely, a need exists for personal care compositions comprising essential oils that have reduced levels of auxiliary fragrance materials, but also a select level and ratio of these materials in combination with a base fragrance and specific terpene materials in order to deliver the fragrance and activity of the essential oil without associated sensitivity problems.
U.S. Pat. No. 5,298,238 to Hussein et al. discloses liquid oral compositions comprising deterpenated and fractionated peppermint oil. The compositions therein comprise very low levels of 1,8-cineole, - and -pinenes and linalool and limonene. US Application 2003/0012830 A1 discloses a topical composition comprising eucalyptol, -pinene and acetone. EP 1048293 A discloses head-lice treatment compositions comprising eucalyptol and limonene in water. WO 98/17749 discloses an essential oil extracted from the shrub Kunzea Ambigua which contains high levels of - and -pinenes. WO 98/17229 discloses medicaments comprising at least 25% eucalyptol, and at least 25% limonene. US Application 2003/0113277 A1 discloses oral care compositions comprising eucalyptol and limonene for masking the taste of phenolics such as triclosan present in the compositions. The above compositions either do not deliver the required reduced level of auxiliary fragrance materials to avoid sensitivity reactions and therefore are not hyposensitive formulae, or do not contain enough auxiliary fragrance materials to generate a well-rounded fragrance or associated aromatherapeutic activity.
It has been found that personal care compositions can be formulated with essential oil component materials that reconstitute the essential oil in the composition to maximize the fragrance and activity associated with the essential oils therein, whilst improving the hyposensitivity of the compositions by selectively blending the constituent fragrance materials. It has further been found that removing the auxiliary fragrance materials entirely lessens the impact of the essential oil, and that by incorporating these materials at low levels and in select ratios with other terpene materials, a mixture is generated having fragrance and activity similar to the pure extracted essential oil that is gentle to skin.